Improvement in steam and air brakes



A. THOMSON.

Steam and Air Brakes.

No.15l634, Patenfedlune 2,1874.

Inv cantor 'UNITED STATES ARGFTBALD THoMsoN,

PATENT Qrrrcn OF CINCINNATI, OI-IIO.

IMPROVEMENT IN STEAM AND AIR BRAKES.

Specification forming part of Letters Patent No. l 51,634, dated June 2, 1874; application filed May 6, 1874.

To all whom it may concern:

Beit known that I, ARCHIBALD THOMSON, of Cincinnati, Hamilton county, State of Ohio, have invented certain new and useful Improvements in Steam or Air Brakes, of which the following is a specication:

My invention relates to devices for operating the brakes of railway-cars by means of steam or compressed air, and consists of an arrangement of pivoted levers and pulleys or sheaves connected with coiled springs attached to the bottom of each car, which, by means of a single' cord attached to the piston under the tender and passing (through the medium of connecting-links) from car to car of the entire train, enables the simultaneous application of the brakes throughout the train by a single continuous stroke of the piston, which is operated from the engine and under the control of the engineer and his assistant only. My invention further embraces the multiplication of power by the peculiar construction and arrc ngement of the levers and pulleys aforesaid, whereby a great pressure is brought to bear upon the brakes by the direct extended motion of the piston of the cylinder under the tender.

Figure 1 is a plan of the adjacent trucks of two railway-cars, showing the system of levers and pulleys, their attachment to the brakes, and the arrangement ofthe cord for operating said levers so as to press the brakes against the car-wheels. Fig. 2 is a plan of a portion of the bottom of a tender, showing the cylinder, piston rod, and cross-head, the safetyvalve, and the jointed pipe by which steam is conveyed from the boiler. Fig. 3 is an axial section of the cylinder, showing the piston, its rod, cross-head, and eye for attaching the cord, the safety-valve, and a portion of the jointed steam-pipe. Fig. 4 is a section through one of the ball-and-socket swiveling-joints of the steam-pipe.

A A are the adjacent ends of two eightwheel railway-cars, each resting upon a truck supported by four wheels. B B B Bll are brakes depending by the usual swinging frames from the bottom of the car. The construction of the two trucks being the same, with one partially broken away in the drawing, one only will be described in detail; but

the letters of reference are used on both on such portions of the drawing as most clearly show the parts or part referred to. Pivoted at the center of the truck, ilra frame, C,which rests at each end upon a step, b b', is a swin ing frame, c c, which carries at each side of its pivot a pulley, d d. The pivot Vof the frame and the axles ofthe pulleys extend below the frame c c and support two circular disks, e e, between which, coiled around the pivot, is a spring, D, the inner end being immovably secured to the pivot and the outer or free end secured to the disks e c', so that the spring shall act, by uncoiling, to move the frame in one direction to release the brakes, being forcibly coiled by the movement of the frame c c in the other direction, when pressure is to be applied to the brakes. Pivoted at one extremity, upon the steps or brackets b b, are two levers of the second class, ff', whose other extremities are connected, by means of the bars or pitmen F F, (having swivelingjoints at each end,) with the extremities of the Aswinging frame c c. At the midlength of the cross-bars b of each brake one end of arms g g connect, the other ends being fastened by a swivelin g connection to the leversff at about one-third ofthe levers length from the fulcrum, where they are pivoted to the steps or brackets b b. A cord, h, passing' around the pulleys in a reversed direction, as shown, is attached upon the tender by means of an eye, K, to the piston-rod I of a steam-cylinder, G.- Upright posts i i at each end of the cars, near the brakes, enable the end of the cord to be secured at the rear of the train, and links 7' serve to connect the cord from car to car. Gr is a steam-cylinder, in which operates a piston, H, whose rod fi, passing through a customary stuffing-box, carries a cross-head, J, moving upon guide-rods 7c 7c, and has an eye, K, to which the cord h is made fast. A pipe, L, leading from the boiler, supplies steam for the operation of the piston, the action of which draws the cross-head and eye forward, and the cord h, being drawn through the pulleys d d', swivels the swinging frame c c upon its axis, (against the action of coiled spring D,) drawing arm c forward and arm c backward,which,

acting through the bars or pitmen F F upon the levers f j" 4presses the brakes B B B B" against the periphery of the car-wheels. rlhe cord h being made continuous from car to car by means ofthe linksj, the stroke of the brakes is nearly simultaneous. lVhen the brakes are to be released, the steam in pipe L is shut off, and by the same movement, or separate valve, if preferred, the steam in cylinderG is exhausted, when, by the recoil of springs D, all the parts are thrown back to their original position. The pipe L, which supplies steam from the boiler to the cylinder, is rendered flexible by means of two or more joints consisting of a thimble, a, having a globular cavity in its interior for the reception of a ball, m, formed upon the end of a length of pipe, which is al lowcd to swivel in said cavity by the chamfering of the tubular end of the thimble. The other end of the thimble is screw-threaded to receive the end of a length of pipe, p, which is shaped in spherical socket form, to engage with and form a seat for said ball, the pipe p being secured by a look-nut, o.

The adjustable safety-valve device is constructed as follows: The stem of the valve N passes through a guide-yoke, q, which is secured to the cylinder by posts o'. A spring, s,

is interposed between the outer face of the valve and the inner face of the yoke, by the pressure of which the valve is kept to its seat against the interior pressure of steam. The posts r are screw-threaded and tted with two lock-nuts, t, each, one on each side of the yoke q. By the adjustment of these nuts the yoke can be forced to or from the valve and the spring power over the valve increased or diminished thereby, so that the valve can be set to blow off or escape steam at any desired pressure, and thus prevent an excessive strain being applied by the engineer tothe brakes.

I claiml The combination of cylinder G, piston H,

cord h, pulleys d d', swinging frame e c', spring D, levers ff', pitnien g g F F, and brakes B Bl B B" b, connected and operating substantially in the manner and for the purpose specifled.

In testimony of which invention I hereunto set my hand.

ARCHIBALD THOMSON. Titnesses HENRY MrLLwAnD, J. L. WAn'rMANN. 

